1. Field of the Invention
This device discloses a portable sequential contaminant detection system which can test samples for contaminants at predetermined timed intervals.
2. Background of the Invention
Over the years, there have been a number of different sampler devices created to improve the ease and accuracy of testing for air-borne contaminants.
U.S. Pat. No. 4,569,235 (Conkle et al.) discloses a portable sequential air sampler having an easily transportable housing containing therein a plurality of interrelated components which allow the air sampler to operate by either a battery or line power. The components include a vacuum pump and rotary valve which are capable of sequentially drawing air through the sampling media. The flow rate control system is operably connected to the vacuum pump in order to maintain the substantially constant flow rate through the sampling media. The air sampler can vary initiation of the sampling operation from 1-999 minutes while varying the sequence of sampling from 1-99 minutes. while maintaining substantially constant air flow through the air sampling procedure.
U.S. Pat. No. 4,576,054 (Lalin) discloses a dual mode gas sampler and pneumatic flow control system. The device has a manually adjustable flow restricting orifice, a two position mode select valve, a flow controller, and a vacuum pump for drawing gas from the atmosphere through a load representing either a single test article with flow being held constant or multiple test articles with pressure head constant.
U.S. Pat. No. 4,589,292 (Delhaye et al.) discloses a process for sampling ambient air at a work place. The process comprises continually withdrawing by means of a pump, a sample of ambient air in the proximity of the respiratory tract of an individual worker filtering the aspirated air for subsequent analysis of filtered-out particles, picking-up the cardiac rhythm of the individual and controlling the flow air of the pump by a signal modulated by the cardiac rhythm of the individual. The apparatus for carrying out this process comprises a sampling tube, a motor driven pump for drawing a sample of ambient air in through the sampling tube, a filter associated with the sampling tube for filtering the air sample, a photo electric device for picking up the cardiac rhythm of the individual and a control circuit for controlling the flow-rate of the pump by a signal modulated by the cardiac rhythm of the individual.
U.S. Pat. No. 5,101,670 (Steger et al.) discloses an automated sampling system for proportional sampling of a fluid stream. The system includes at least one syringe type sampler container having an inlet and outlet at one end and a piston therein displaceable to fill and discharge the container, means for connecting the inlet of the sample container to the fluid stream, for withdrawing samples to the container, flow sensor means positionable in the fluid stream for continuously measuring the flow rate of the fluid stream and providing a continuous first control signal varying in accordance with the measured flow rate, a piston drive means for withdrawing the syringe piston at a rate in accordance with the first control signal, and limited means for stopping the withdrawing displacement of the piston at a predetermined end point in its axial movement.
U.S. Pat. No. 4,158,035 (Haase et al.) discloses a multiple sample micropipette. The device comprises a housing, a plurality of tubes mounted on the housing, each of the tubes having a passage extending therethrough, flexible impervious membrane means extending across the passages to divide each of the passages into a first passage section and a second passage section, an incompressible flowable material. A mechanism is provided for moving the flowable material to deflect the membrane in opposite directions whereby liquid can be drawn into and expelled from the tubes.
U.S. Pat. No. 4,215,092 (Suovaniemi et al.) discloses a multichannel pipette disclosed having an improved arrangement of replaceable tip containers in which the individual tip containers are connected together by flexible connecting members which are deformable to permit connection of the tip containers to differing configuration of tip cones.